@ARTICLE{Bjerring_Rikke_Description_2008, author={Bjerring, Rikke and Nykänen, Mirva and Sarmaja-Korjonen, Kaarina and Sinev, Artem and Jensen, Karina and Nevalainen, Liisa and Szeroczyńska, Krystyna and Zawisza, Edyta}, volume={Vol. 25}, journal={Studia Quaternaria}, pages={47-53}, howpublished={online}, year={2008}, publisher={Committee for Quaternary Research PAS}, publisher={Institute of Geological Sciences PAS}, abstract={This paper gives a description of the head shield of Alona protzi, a rare species of Cladocera (water fleas) whose separated head shield has not yet been described in detail. Subfossil head shields of A. protzi were found in sediment cores taken from lakes in Denmark, Sweden, Finland, Estonia and Poland. Despite the rarity of the species this suggests a wide distribution of A. protzi in northern Europe. The ecology of A. protzi is poorly known. The environmental spectrum of the finding sites was wide and ranged from relatively nutrient poor clear water lakes to eutrophic turbid water lakes, indicating that A. protzi is not narrowly restricted. Most of the lakes were, however, meso-eutrophic with neutral to high pH, and with a relatively low abundance of submerged macrophytes. However, we cannot exclude the possibility that A. protzi mainly lives in groundwater and is only occasionally transported into lakes.}, type={Article}, title={Description of the subfossil head shield of Alona protzi Hartwig 1900 (Anomopoda, Chydoridae) and the environmental characteristics of its finding sites}, URL={http://journals.pan.pl/Content/118936/PDF-MASTER/s_47_53.pdf}, keywords={Subfossil Cladocera, Alona protzi, head shield, description, paleolimnology}, }